| Message ID | 1574816450.13250.2.camel@hbabu-laptop (mailing list archive) |
|---|---|
| Headers | show |
| Series | powerpc/vas: Page fault handling for user space NX requests | expand |
Hi Haren, On 27/11/19 12:00 pm, Haren Myneni wrote: > Haren Myneni (14): > powerpc/vas: Describe vas-port and interrupts properties > Revert "powerpc/powernv: remove the unused vas_win_paste_addr and > vas_win_id functions" > powerpc/vas: Define nx_fault_stamp in coprocessor_request_block > powerpc/vas: Setup IRQ mapping and register port for each window > powerpc/vas: Setup fault window per VAS instance > powerpc/VAS: Setup fault handler per VAS instance > powerpc/vas: Read and process fault CRBs > powerpc/vas: Take reference to PID and mm for user space windows > powerpc/vas: Update CSB and notify process for fault CRBs > powerpc/vas: Print CRB and FIFO values > powerpc/vas: Do not use default credits for receive window > powerpc/VAS: Return credits after handling fault > powerpc/vas: Display process stuck message > powerpc/vas: Free send window in VAS instance after credits returned In future, please send the patches in reply to the cover letter (and for series that don't have a cover letter, send patch 2 onwards as a reply to patch 1). You may want to consider using git send-email which automates all this for you. Thanks,
Applications send compression / decompression requests to NX with COPY/PASTE instructions. When NX is processing these requests, can hit fault on the request buffer (not in memory). It issues an interrupt and pastes fault CRB in fault FIFO. Expects kernel to handle this fault and return credits for both send and fault windows after processing. This patch series adds IRQ and fault window setup, and NX fault handling: - Read IRQ# from "interrupts" property and configure IRQ per VAS instance. - Set port# for each window to generate an interrupt when noticed fault. - Set fault window and FIFO on which NX paste fault CRB. - Setup fault handler (as kernel thread) per VAS instance. - When receiving an interrupt, Read CRBs from fault FIFO and update coprocessor_status_block (CSB) in the corresponding CRB with translation failure (CSB_CC_TRANSLATION). After issuing NX requests, process polls on CSB address. When it sees translation error, can touch the request buffer to bring the page in to memory and reissue NX request. - If copy_to_user fails on user space CSB address, OS sends SEGV signal. Tested these patches with NX-GZIP support and will be posting this series soon. Patch 2: Revert 452d23c0f6bd97f2 - Using vas_win_id() and vas_win_paste_addr() Patch 3: Define nx_fault_stamp on which NX writes fault status for the fault CRB Patch 4: IRQ and port setup Patches 5 and 6: Setup fault window and fault handler per each VAS instance. fault window is used for NX to paste fault CRB in FIFO. A kernel thread is created to handle faults on each VAS. Patches 7, 9 and 10: Read and process CRBs from fault FIFO and notify tasks by updating CSB or through signals. Patch 8: Reference to pid and mm so that pid is not used until window closed. Needef for multi thread application where child can open a window and can be used by parent later. Patches 11 and 12: Return credits for send and fault windows after handling faults. Patch 14: Fix closing send window after all credits are returned. This issue happens only for user space requests. No page faults on kernel request buffer. Haren Myneni (14): powerpc/vas: Describe vas-port and interrupts properties Revert "powerpc/powernv: remove the unused vas_win_paste_addr and vas_win_id functions" powerpc/vas: Define nx_fault_stamp in coprocessor_request_block powerpc/vas: Setup IRQ mapping and register port for each window powerpc/vas: Setup fault window per VAS instance powerpc/VAS: Setup fault handler per VAS instance powerpc/vas: Read and process fault CRBs powerpc/vas: Take reference to PID and mm for user space windows powerpc/vas: Update CSB and notify process for fault CRBs powerpc/vas: Print CRB and FIFO values powerpc/vas: Do not use default credits for receive window powerpc/VAS: Return credits after handling fault powerpc/vas: Display process stuck message powerpc/vas: Free send window in VAS instance after credits returned .../devicetree/bindings/powerpc/ibm,vas.txt | 5 + arch/powerpc/include/asm/icswx.h | 32 +- arch/powerpc/include/asm/vas.h | 10 + arch/powerpc/platforms/powernv/Makefile | 2 +- arch/powerpc/platforms/powernv/vas-debug.c | 2 +- arch/powerpc/platforms/powernv/vas-fault.c | 408 +++++++++++++++++++++ arch/powerpc/platforms/powernv/vas-window.c | 192 +++++++++- arch/powerpc/platforms/powernv/vas.c | 87 ++++- arch/powerpc/platforms/powernv/vas.h | 54 ++- 9 files changed, 769 insertions(+), 23 deletions(-) create mode 100644 arch/powerpc/platforms/powernv/vas-fault.c